Ten-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/023,506, filed on Jan. 25, 2008, which is hereby incorporated in itsentirety herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact ten speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets include first, second and third members. A first interconnectingmember continuously interconnects the third member of the firstplanetary gear set with the first member of the second planetary gearset. A second interconnecting member continuously interconnects thesecond member of the second planetary gear set with the third member ofthe third planetary gear set. A third interconnecting membercontinuously interconnects the first member of the third planetary gearset with the third member of the fourth planetary gear set. Six torquetransmitting mechanisms selectively engageable to interconnects one ofthe first, second, and third members with at least one other of thefirst members, second members, third members and a stationary member.The torque transmitting mechanisms are selectively engageable incombinations of at least four to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.

In another embodiment of the present invention, a first of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe first member of the first planetary gear set with the first memberof the fourth planetary gear set.

In yet another embodiment of the present invention, a second of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe first member of the first planetary gear set with the second memberof the fourth planetary gear set.

In yet another embodiment of the present invention, a third of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe input member with at least one of the first member of the thirdplanetary gear set and the third member of the fourth planetary gearset.

In yet another embodiment of the present invention, a fourth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the second member of the second planetary gear set andthe third member of the third planetary gear set with the second memberof the fourth planetary gear set.

In yet another embodiment of the present invention, a fifth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the third member of the first planetary gear set and thefirst member of the second planetary gear set with the stationarymember.

In yet another embodiment of the present invention, a sixth of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe third member of the second planetary gear set with the stationarymember.

In yet another embodiment of the present invention, the third member ofthe first planetary gear set and first member of the second, third andfourth planetary gear sets are sun gears, the second members of thefirst, second, third and fourth planetary gear sets are carrier membersand the first member of the first planetary gear set and third member ofthe second, third and fourth planetary gear sets are ring gears.

In still another embodiment of the present invention, the input memberis continuously interconnected with the second member of the firstplanetary gear set and the output member is continuously interconnectedwith the second member of the third planetary gear set.

In still another embodiment of the present invention, two of the torquetransmitting mechanisms are brakes and four of the torque transmittingmechanisms are clutches.

In still another embodiment of the present invention, the stationarymember is a transmission housing.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic illustration of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of the tenspeed automatic transmission of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. A third component or element of a firstplanetary gear set is permanently coupled to a first component orelement of the second planetary gear set. A second component or elementof a second planetary gear set is permanently coupled to a thirdcomponent or element of the third planetary gear set. A first componentor element of the third planetary gear set is permanently coupled tothird component or element of the fourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the second node 14B of the firstplanetary gear set 14. The output member 22 is coupled to the secondnode 18B of the third planetary gear set 18. The third node 14C of thefirst planetary gear set 14 is coupled to the first node 16A of thesecond planetary gear set 16. The second node 16B of the secondplanetary gear set 16 is coupled to the third node 18C of the thirdplanetary gear set 18. The first node 18A of the third planetary gearset 18 is coupled to the third node 20C of the fourth planetary gear set20.

A first clutch 26 selectively connects the first node 14A of the firstplanetary gear set 14 with the first node 20A of the fourth planetarygear set 20. A second clutch 28 selectively connects the first node 14Aof the first planetary gear set 14 with the second node 20B of thefourth planetary gear set 20. A third clutch 30 selectively connects thesecond node 14B of the second planetary gear set 14 to the third node20C of the fourth planetary gear set 20. A fourth clutch 32 selectivelyconnects the second node 16B of the second planetary gear set 16 and thethird node 18C of the third planetary gear set 18 with the second node20B of the fourth planetary gear set 20. A first brake 34 selectivelyconnects the third node 14C of the first planetary gear set 14 to astationary member or transmission housing 50. A second brake 36selectively connects the third node 16C of the second planetary gear set16 to a stationary member or transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14C, aring gear member 14A and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14C is connected for common rotation with a first shaft orintermediate member 42. The ring gear member 14A is connected for commonrotation with a second shaft or intermediate member 44. The planetcarrier member 14B is connected for common rotation with input shaft ormember 12. The set of planet gears 14D are each configured to intermeshwith both the sun gear member 14C and the ring gear member 14A.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16A is connected for common rotation with first shaft orintermediate member 42 and with a third shaft or intermediate member 46.The ring gear member 16C is connected to brake 36. The planet carriermember 16B is connected for common rotation with a fourth shaft orintermediate member 48. The planet gears 16D are each configured tointermesh with both the sun gear member 16A and the ring gear member16C.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18A is connected for common rotation with a fifth intermediatemember 52. The ring gear member 18C is connected for common rotationwith a fourth shaft or intermediate member 48. The planet carrier member18B is connected for common rotation with the output shaft or member 22.The planet gears 18D are each configured to intermesh with both the sungear member 18A and the ring gear member 18C.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The planet gears20D are each configured to intermesh with both the sun gear member 20Aand the ring gear member 20C. The sun gear member 20A is connected forcommon rotation with a sixth shaft or intermediate member 54. The ringgear member 20C is connected for common rotation with fifth shaft orintermediate member 52. The planet carrier member 20B is connected forcommon rotation with a seventh intermediate member 56.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28, 30, 32 and brakes34 and 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the second shaft or intermediate member 44 with the sixth shaftor intermediate member 54. The second clutch 28 is selectivelyengageable to connect the second shaft or intermediate member 44 withthe seventh shaft or intermediate member 56. The third clutch 30 isselectively engageable to connect the input shaft or member 12 with thefifth shaft or intermediate member 52. The fourth clutch 32 isselectively engageable to connect the fourth shaft or intermediatemember 48 with the seventh shaft or intermediate member 56. The firstbrake 34 is selectively engageable to connect the third shaft orintermediate member 46 with the stationary element or the transmissionhousing 50 in order to restrict the member 46 from rotating relative tothe transmission housing 50. The second brake 36 is selectivelyengageable to connect the ring gear member 16C with the stationaryelement or the transmission housing 50 in order to restrict the member16C from rotating relative to the transmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the embodiment ofthe ten speed transmission 10 will be described. It will be appreciatedthat transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with triple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, fourth clutch 32, first brake 34 and second brake 36),as will be explained below. FIG. 3 is a truth table presenting thevarious combinations of torque-transmitting mechanisms that areactivated or engaged to achieve the various gear states. An “X” in thebox means that the particular clutch or brake is engaged to achieve thedesired gear state. An “∘” represents that the particular torquetransmitting device (i.e. a brake or clutch) is on or active, but notcarrying torque. Actual numerical gear ratios of the various gear statesare also presented although it should be appreciated that thesenumerical values are exemplary only and that they may be adjusted oversignificant ranges to accommodate various applications and operationalcriteria of the transmission 10. An example of the gear ratios that maybe obtained using the embodiments of the present invention are alsoshown in FIG. 3. Of course, other gear ratios are achievable dependingon the gear diameter, gear teeth count and gear configuration selected.

To establish a reverse gear, the first clutch 26, fourth clutch 32,first brake 34 and second brake 36 are engaged or activated. The firstclutch 26 connects the second shaft or intermediate member 44 with thesixth shaft or intermediate member 54. The fourth clutch 32 connects thefourth shaft or intermediate member 48 with the seventh shaft orintermediate member 56. The first brake 34 connects the third shaft orintermediate member 46 with the stationary element or the transmissionhousing 50 in order to restrict the member 46 from rotating relative tothe transmission housing 50. The second brake 36 connects the ring gearmember 16C with the stationary element or the transmission housing 50 inorder to restrict the member 16C from rotating relative to thetransmission housing 50. Likewise, the ten forward ratios are achievedthrough different combinations of clutch and brake engagement, as shownin FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches not specifically referenced in a given gear state areinactive or disengaged and, second of all, that during gear shifts,i.e., changes of gear state, between at least adjacent gear states, aclutch engaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the third member of the first planetary gear set withthe first member of the second planetary gear set; a secondinterconnecting member continuously interconnecting the second member ofthe second planetary gear set with the third member of the thirdplanetary gear set; a third interconnecting member continuouslyinterconnecting the first member of the third planetary gear set withthe third member of the fourth planetary gear set; and six torquetransmitting mechanisms selectively engageable to interconnect one ofthe first, second, and third members with at least one other of thefirst members, second members, third members and a stationary member,and wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least four to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 2. The transmission of claim 1wherein a first of the six torque transmitting mechanisms is selectivelyengageable to interconnect the first member of the first planetary gearset with the first member of the fourth planetary gear set.
 3. Thetransmission of claim 2 wherein a second of the six torque transmittingmechanisms is selectively engageable to interconnect the first member ofthe first planetary gear set with the second member of the fourthplanetary gear set.
 4. The transmission of claim 3 wherein a third ofthe six torque transmitting mechanisms is selectively engageable tointerconnect the input member with at least one of the first member ofthe third planetary gear set and the third member of the fourthplanetary gear set.
 5. The transmission of claim 4 wherein a fourth ofthe six torque transmitting mechanisms is selectively engageable tointerconnect at least one of the second member of the second planetarygear set and the third member of the third planetary gear set with thesecond member of the fourth planetary gear set.
 6. The transmission ofclaim 5 wherein a fifth of the six torque transmitting mechanisms isselectively engageable to interconnect at least one of the third memberof the first planetary gear set and the first member of the secondplanetary gear set with the stationary member.
 7. The transmission ofclaim 6 wherein a sixth of the six torque transmitting mechanisms isselectively engageable to interconnect the third member of the secondplanetary gear set with the stationary member.
 8. The transmission ofclaim 1 wherein the third member of the first planetary gear set andfirst member of the second, third and fourth planetary gear sets are sungears, the second members of the first, second, third and fourthplanetary gear sets are carrier members and the first member of thefirst planetary gear set and third member of the second, third andfourth planetary gear sets are ring gears.
 9. The transmission of claim1 wherein the input member is continuously interconnected with thesecond member of the first planetary gear set and wherein the outputmember is continuously interconnected with the second member of thethird planetary gear set.
 10. The transmission of claim 1 wherein two ofthe torque transmitting mechanisms are brakes and four of the torquetransmitting mechanisms are clutches.
 11. The transmission of claim 1wherein the stationary member is a transmission housing.
 12. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members, wherein the input member is continuouslyinterconnected with the second member of the first planetary gear setand wherein the output member is continuously interconnected with thesecond member of the third planetary gear set; a first interconnectingmember continuously interconnecting the third member of the firstplanetary gear set with the first member of the second planetary gearset; a second interconnecting member continuously interconnecting thesecond member of the second planetary gear set with the third member ofthe third planetary gear set; a third interconnecting membercontinuously interconnecting the first member of the third planetarygear set with the third member of the fourth planetary gear set; a firsttorque transmitting mechanism selectively engageable to interconnect thefirst member of the first planetary gear set with the first member ofthe fourth planetary gear set; a second torque transmitting mechanismselectively engageable to interconnect the first member of the firstplanetary gear set with the second member of the fourth planetary gearset; a third torque transmitting mechanism selectively engageable tointerconnect the input member with at least one of the first member ofthe third planetary gear set and the third member of the fourthplanetary gear set; a fourth torque transmitting mechanism selectivelyengageable to interconnect at least one of the second member of thesecond planetary gear set and the third member of the third planetarygear set with the second member of the fourth planetary gear set; afifth torque transmitting mechanism selectively engageable tointerconnect at least one of the third member of the first planetarygear set and the first member of the second planetary gear set with thestationary member; and a sixth torque transmitting mechanism selectivelyengageable to interconnect the third member of the second planetary gearset with the stationary member, and wherein the torque transmittingmechanisms are selectively engageable in combinations of at least fourto establish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 13. Thetransmission of claim 12 wherein the third member of the first planetarygear set and first member of the second, third and fourth planetary gearsets are sun gears, the second members of the first, second, third andfourth planetary gear sets are carrier members and the first member ofthe first planetary gear set and third member of the second, third andfourth planetary gear sets are ring gears.
 14. The transmission of claim12 wherein the stationary member is a transmission housing.
 15. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having sun gear,carrier member and ring gear, wherein the input member is continuouslyinterconnected with the carrier member of the first planetary gear setand wherein the output member is continuously interconnected with thecarrier member of the third planetary gear set; a first interconnectingmember continuously interconnecting the sun gear of the first planetarygear set with the sun gear of the second planetary gear set; a secondinterconnecting member continuously interconnecting the carrier memberof the second planetary gear set with the ring gear of the thirdplanetary gear set; a third interconnecting member continuouslyinterconnecting the sun gear of the third planetary gear set with thering gear of the fourth planetary gear set; a first torque transmittingmechanism selectively engageable to interconnect the ring gear member ofthe first planetary gear set with the sun gear of the fourth planetarygear set; a second torque transmitting mechanism selectively engageableto interconnect the ring gear of the first planetary gear set with thecarrier member of the fourth planetary gear set; a third torquetransmitting mechanism selectively engageable to interconnect the inputmember with at least one of the sun gear of the third planetary gear setand the ring gear of the fourth planetary gear set; a fourth torquetransmitting mechanism selectively engageable to interconnect at leastone of the carrier member of the second planetary gear set and the ringgear of the third planetary gear set with the carrier member of thefourth planetary gear set; a fifth torque transmitting mechanismselectively engageable to interconnect at least one of the sun gear ofthe first planetary gear set and the sun gear member of the secondplanetary gear set with the stationary member; and a sixth torquetransmitting mechanism selectively engageable to interconnect the ringgear of the second planetary gear set with the stationary member, andwherein the torque transmitting mechanisms are selectively engageable incombinations of at least four to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 16. The transmission of claim 15 wherein thestationary member is a transmission housing.